The XRMS experiment on the Gd{sub 5}Ge{sub 4} system has shown that, below the Neel temperature, T{sub N} = 127 K, the magnetic unit cells is the same as the chemical unit cell. From azimuth scans and the Q dependence of the magnetic scattering, all three Gd sites in the structure were determined to be in the same magnetic space group Pnma. The magnetic moments are aligned along the c-axis and the c-components of the magnetic moments at the three different sites are equal. The ferromagnetic slabs are stacked antiferromagnetically along the b-direction. They found an unusual order parameter curve in Gd{sub 5}Ge{sub 4}. A spin-reorientation transition is a possibility in Gd{sub 5}Ge{sub 4}, which is similar to the Tb{sub 5}Ge{sub 4} case. Tb{sub 5}Ge{sub 4} possesses the same Sm{sub 5}Ge{sub 4}-type crystallographic structure and the same magnetic space group as Gd{sub 5}Ge{sub 4} does. The difference in magnetic structure is that Tb{sub 5}Ge{sub 4} has a canted one but Gd{sub 5}Ge{sub 4} has nearly a collinear one in the low temperature antiferromagnetic phase. The competition between the magneto-crystalline anisotropy and the nearest-neighbor magnetic exchange interactions may allow a 3-dimensional canted antiferromagnetic structure in Tb{sub 5}Ge{sub 4}. The spin-reorientation transition …

A Monte Carlo study of a generic search for new resonances beyond the Standard Model (SM) in the CMS experiment is presented. The resonances are axigluon, coloron, E{sub 6} diquark, excited quark, W{prime}, Z{prime}, and the Randall-Sundrum graviton which decay to dijets. The dijet resonance cross section that the CMS can expect to discover at a 5{sigma} significance or to exclude at 95% confidence level for integrated luminosities of 100 pb{sup -1}, 1 fb{sup -1}, and 10 fb{sup -1} is evaluated. It is shown that a 5{sigma} discovery of a multi-TeV dijet resonance is possible for an axigluon, excited quark, and E{sub 6} diquark. However, a 5{sigma} discovery can not be projected with confidence for a W{prime}, Z{prime} and the Randall-Sundrum graviton. On the other hand, 95% CL exclusion mass regions can be measured for all resonances at high luminosities. In the second part of this dissertation, the analyses of the 2006 test beam data from the combined electromagnetic and hadronic barrel calorimeters are presented. The CMS barrel calorimeters response to a variety of beam particles in a wide momenta range (1 to 350 GeV/c) is measured. Furthermore, using these beam data, the expected performance of the barrel calorimeters to …

The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered {approx} 500 spectroscopically confirmed SNe Ia with densely sampled (once every {approx} 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents {approx} 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 {micro}g L{sup -1} or better were found for P, Mn, Fe, Cu, and Zn in a 60 {micro}L injection in a physiological saline matrix.

This thesis presents a new determination of {Lambda}{sub QCD} from Next-to-Leading Order QCD fits to the Q{sup 2} dependence of neutrino-iron structure functions. This is the first measurement of {Lambda}{sub QCD} which uses a theoretical model that fully accounts for heavy quark production. Compared with previous neutrino measurements, the result has improved understanding of the largest systematic uncertainties on the muon and hadron energy scales. These improvements lead to one of the most precise determination of {alpha}{sub S} at moderate Q{sup 2}. NuTeV is a neutrino-iron deep inelastic scattering (DIS) experiment that collected data during 1996-97 at Fermilab. The key features of NuTeV include its sign-selected beam which produced separate high purity neutrino and antineutrino beams, and its continuous calibration beam which enabled NuTeV to considerably improve the knowledge of energy scales which have dominated uncertainties in the previous measurements.

In Part I, three independent models of Fermilab's Booster synchrotron are presented. All three models are constructed to investigate and explore the effects of unavoidable machine errors on a proton beam under the influence of space-charge effects. The first is a stochastic noise model. Electric current fluctuations arising from power supplies are ubiquitous and unavoidable and are a source of instabilities in accelerators of all types. A new noise module for generating the Ornstein-Uhlenbeck (O-U) stochastic noise is first created and incorporated into the existing Object-oriented Ring Beam Injection and Tracking (ORBIT-FNAL) package. After being convinced with a preliminary model that the noise, particularly non-white noise, does matter to beam quality, we proceeded to measure directly current ripples and common-mode voltages from all four Gradient Magnet Power Supplies (GMPS). Then, the current signals are Fourier-analyzed. Based upon the power spectra of current signals, we tune up the Ornstein-Uhlnbeck noise model. As a result, we are able to closely match the frequency spectra between current measurements and the modeled O-U stochastic noise. The stochastic noise modeled upon measurements is applied to the Booster beam in the presence of the full space-charge effects. This noise model, accompanied by a suite of beam …

A measurement of the fraction, f{sup +}, of right-handed W bosons produced in top quark decays is presented. This analysis is based on a sample corresponding to an integrated luminosity of 370 pb{sup -1}, collected by the D0 detector at the Fermilab Tevatron p{bar p} Collider at {radical}s = 1.96 TeV. The helicity angle, {theta}*, is reconstructed for each lepton. f{sup +} is determined by comparing the cos {theta}* distribution from the data with that for the expected background and signal for various values of f{sup +}. The fraction of longitudinal W bosons, f{sup 0}, is assumed to be 0.7 as predicted by the standard model. This yields f{sup +} = 0.109 {+-} 0.094 (stat) {+-} 0.063 (syst), consistent with the standard model prediction of f{sup +} = 3.6x 10{sup -4}. The possibility that both f{sup +} and f{sup 0} stray from standard model values is also investigated. In this case cos {theta}* distributions for each possible W helicity state, along with the backgrounds, are fit to the cos {theta}* distribution for the data. The best fit values are f{sup +} = 0.82 {+-} 0.30(stat) and f{sup 0} = -0.58 {+-} 0.50(stat).

A search for neutral Higgs bosons decaying into tau pairs is presented using data in p{bar p} collisions at {radical}s = 1.96 TeV. One of the tau leptons is identified via its decay into an electron or muon and the other via its decay into a hadronic final state. The data, corresponding to an integrated luminosity of around 1.0 fb{sup -1}, were collected with the D0 detector at the Fermilab Tevatron collider between April 2002 and February 2006. No significant excess of events above the background expectation is observed and limits on the cross section times branching ratio for neutral Higgs bosons decaying into tau pairs, p{bar p} {yields} {phi} {yields} {tau}{sup +}{tau}{sup -}, are set. The cross section limits are interpreted as exclusions in the parameter space of the minimal supersymmetric Standard Model, resulting in exclusions in the range 40 < tan{beta} < 70 for M{sub A} < 200 GeV. Finally, the effect of Higgs bosons with a large total width is considered and the first model independent correction to the cross section limits for the width effect is presented.

We present results of a search for single top quark production in p{bar p} collisions using a dataset of approximately 1 fb{sup -1} collected with the D0 detector. This analysis considers the muon+jets and electron+jets final states and makes use of Bayesian neural networks to separate the expected signals from backgrounds. The observed excess is associated with a p-value of 0.081%, assuming the background-only hypothesis, which corresponds to an excess over background of 3.2 standard deviations for a Gaussian density. The p-value computed using the SM signal cross section of 2.9 pb is 1.6%, corresponding to an expected significance of 2.2 standard deviations. Assuming the observed excess is due to single top production, we measure a single top quark production cross section of {sigma}(p{bar p} {yields} tb + X, tqb + X) = 4.4 {+-} 1.5 pb.

The use of boron neutron capture to boost tumor dose in fast neutron therapy has been investigated at several fast neutron therapy centers worldwide. This treatment is termed boron neutron capture enhanced fast neutron therapy (BNCEFNT). It is a combination of boron neutron capture therapy (BNCT) and fast neutron therapy (FNT). It is believed that BNCEFNT may be useful in the treatment of some radioresistant brain tumors, such as glioblastoma multiform (GBM). A boron neutron capture enhanced fast neutron therapy assembly has been designed for the Fermilab Neutron Therapy Facility (NTF). This assembly uses a tungsten filter and collimator near the patient's head, with a graphite reflector surrounding the head to significantly increase the dose due to boron neutron capture reactions. The assembly was designed using Monte Carlo radiation transport code MCNP version 5 for a standard 20x20 cm{sup 2} treatment beam. The calculated boron dose enhancement at 5.7-cm depth in a water-filled head phantom in the assembly with a 5x5 cm{sup 2} collimation was 21.9% per 100-ppm {sup 10}B for a 5.0-cm tungsten filter and 29.8% for a 8.5-cm tungsten filter. The corresponding dose rate for the 5.0-cm and 8.5-cm thick filters were 0.221 and 0.127 Gy/min, respectively; about …

The top quark, the most recently discovered quark, is the most massive known fundamental fermion. Precision measurements of its mass, a free parameter in the Standard Model of particle physics, can be used to constrain the mass of the Higgs Boson. In addition, deviations in the mass as measured in different channels can provide possible evidence for new physics. We describe a measurement of the top quark mass in the decay channel with two charged leptons, known as the dilepton channel, using data collected by the CDF II detector from p{bar p} collisions with {radical}s = 1.96 TeV at the Fermilab Tevatron. The likelihood in top mass is calculated for each event by convolving the leading order matrix element describing q{bar q} {yields} t{bar t} {yields} b{ell}{nu}{sub {ell}}{bar b}{ell}'{nu}{sub {ell}'} with detector resolution functions. The presence of background events in the data sample is modeled using similar calculations involving the matrix elements for major background processes. In a data sample with integrated luminosity of 1.0 fb{sup -1}, we observe 78 candidate events and measure M{sub t} = 164.5 {+-} 3.9(stat.) {+-} 3.9(syst.) GeV/c{sup 2}, the most precise measurement of the top quark mass in this channel to date.

Polymeric materials have been prevalent in our everyday lives for quite a long time. Most of today's polymeric materials are derived from nonrenewable petroleum-based feedstocks. Instabilities in the regions where petroleum is drilled, along with an increased demand in petroleum, have driven the price of crude oil to record high prices. This, in effect, increases the price of petroleum-based polymeric materials, which has caused a heightened awareness of renewable alternatives for polymeric feedstocks. Cellulose, starch, proteins and natural oils have all been examined as possible polymeric feedstocks. Natural oils are commercially available on a large scale and are relatively cheap. It is projected that the U.S. alone will produce 21 billion pounds of soybean oil in the period 2008/2009. Natural oils also have the advantages of inherent biodegradability, low toxicity, high purity and ready availability. Most natural oils possess a triglyceride structure as shown in Figure 1. Most natural oils have a unique distribution of fatty acid side chains, along with varying degrees of unsaturation per triglyceride. Common fatty acid side chains in naturally occurring oils are palmitic acid (C16:0), a 16 carbon fatty acid with no unsaturation; stearic acid (C18:0), an 18 carbon fatty acid with no unsaturation; oleic …

Self-assembly is a powerful tool in forming structures with nanoscale dimensions. Self-assembly of macromolecules provides an efficient and rapid pathway for the formation of structures from the nanometer to micrometer range that are difficult, if not impossible to obtain by conventional lithographic techniques [1]. Depending on the morphologies obtained (size, shape, periodicity, etc.) these self-assembled systems have already been applied or shown to be useful for a number of applications in nanotechnology [2], biomineralization [3, 4], drug delivery [5, 6] and gene therapy [7]. In this respect, amphiphilic block copolymers that self-organize in solution have been found to be very versatile [1]. In recent years, polymer-micellar systems have been designed that are adaptable to their environment and able to respond in a controlled manner to external stimuli. In short, synthesis of 'nanoscale objects' that exhibit 'stimulus-responsive' properties is a topic gathering momentum, because their behavior is reminiscent of that exhibited by proteins [8]. By integrating environmentally sensitive homopolymers into amphiphilic block copolymers, smart block copolymers with self assembled supramolecular structures that exhibit stimuli or environmentally responsive properties can be obtained [1]. Several synthetic polymers are known to have environmentally responsive properties. Changes in the physical, chemical or biochemical environment of …

The authors study on the rare decay K{sub L} {yields} {pi}{sup 0}{gamma}{gamma}, measure a{sub V}, and branching ratio by analyzing 96, 97 and 99 data. The measurements were taken by KTeV at Fermi National Accelerator Laboratory. After all cuts, they have 1982 K{sub L} {yields} {pi}{sup 0}{gamma}{gamma} candidate. The background level is estimated as 30%. K{sub L} {yields} {pi}{sup 0}{gamma}{gamma} branching ratio is measured as (1.29 {+-} 0.03(stat) {+-} 0.04(sys)) x 10{sup -6}. By using D'Ambrosio's theory to fit a{sub V}, a{sub V} = -(-0.31 {+-} 0.05(stat) {+-} 0.07(sys)).

In recent years the study of stem and progenitor cells has moved to the forefront of research. Since the isolation of human hematopoietic stem cells in 1988 and the subsequent discovery of a self renewing population of multipotent cells in many tissues, many researchers have envisioned a better understanding of development and potential clinical usage in intractable diseases. Both these goals, however, depend on a solid understanding of the intracellular and extracellular forces that cause stem cells to differentiate to a specific cell fate. Many diseases of large scale cell loss have been suggested as candidates for stem cell based treatments. It is proposed that replacing the function of the damaged or defective cells by specific differentiation of stem or progenitor cells could treat the disease. Before cells can be directed to specific lineages, the mechanisms of differentiation must be better understood. Differentiation in vivo is an intensively complex system that is difficult to study. The goal of this research is to develop further understanding of the effects of soluble and extracellular matrix (ECM) cues on the differentiation of neural progenitor cells with the use of a simplified in vitro culture system. Specific research objectives are to study the differentiation …

A capillary electrophoresis (CE) method is developed to determine both NAD{sup +} and NADH levels in a single cell, based on an enzymatic cycling reaction. The detection limit can reach down to 0.2 amol NAD{sup +} and 1 amol NADH on a home-made CE-LIF setup. The method showed good reproducibility and specificity. After an intact cell was injected into the inlet of a capillary and lysed using a Tesla coil, intracellular NAD{sup +} and NADH were separated, incubated with the cycling buffer, and quantified by the amount of fluorescent product generated. NADH and NAD{sup +} levels of single cells of three cell lines and primary astrocyte culture were determined using this method. Comparing cellular NAD{sup +} and NADH levels with and without exposure to oxidative stress induced by H{sub 2}O{sub 2}, it was found that H9c2 cells respond to the stress by reducing both cellular NAD{sup +} and NADH levels, while astrocytes respond by increasing cellular NADH/NAD{sup +} ratio.

The Fermilab Tevatron is currently the world's highest energy colliding beam facility. Its counter-rotating proton and antiproton beams collide at 2 TeV center-of-mass. Delivery of such intense beam fluxes to experiments has required improved knowledge of the Tevatron's beam optical lattice. An oscillating dipole magnet, referred to as an AC dipole, is one of such a tool to non-destructively assess the optical properties of the synchrotron. We discusses development of an AC dipole system for the Tevatron, a fast-oscillating (f {approx} 20 kHz) dipole magnet which can be adiabatically turned on and off to establish sustained coherent oscillations of the beam particles without affecting the transverse emittance. By utilizing an existing magnet and a higher power audio amplifier, the cost of the Tevatron AC dipole system became relatively inexpensive. We discuss corrections which must be applied to the driven oscillation measurements to obtain the proper interpretation of beam optical parameters from AC dipole studies. After successful operations of the Tevatron AC dipole system, AC dipole systems, similar to that in the Tevatron, will be build for the CERN LHC. We present several measurements of linear optical parameters (beta function and phase advance) for the Tevatron, as well as studies of …

In solid state chemistry, numerous investigations have been attempted to address the relationships between chemical structure and physical properties. Such questions include: (1) How can we understand the driving forces of the atomic arrangements in complex solids that exhibit interesting chemical and physical properties? (2) How do different elements distribute themselves in a solid-state structure? (3) Can we develop a chemical understanding to predict the effects of valence electron concentration on the structures and magnetic ordering of systems by both experimental and theoretical means? Although these issues are relevant to various compound classes, intermetallic compounds are especially interesting and well suited for a joint experimental and theoretical effort. For intermetallic compounds, the questions listed above are difficult to answer since many of the constituent atoms simply do not crystallize in the same manner as in their separate, elemental structures. Also, theoretical studies suggest that the energy differences between various structural alternatives are small. For example, Al and Ga both belong in the same group on the Periodic Table of Elements and share many similar chemical properties. Al crystallizes in the fcc lattice with 4 atoms per unit cell and Ga crystallizes in an orthorhombic unit cell lattice with 8 atoms …

The generation, motion, and interaction of dislocations play key roles during the plastic deformation process of crystalline solids. 3D Dislocation Dynamics has been employed as a mesoscale simulation algorithm to investigate the collective and cooperative behavior of dislocations. Most current research on 3D Dislocation Dynamics is based on the solutions available in the framework of classical isotropic elasticity. However, due to some degree of elastic anisotropy in almost all crystalline solids, it is very necessary to extend 3D Dislocation Dynamics into anisotropic elasticity. In this study, first, the details of efficient and accurate incorporation of the fully anisotropic elasticity into 3D discrete Dislocation Dynamics by numerically evaluating the derivatives of Green's functions are described. Then the intrinsic properties of perfect dislocations, including their stability, their core properties and disassociation characteristics, in newly discovered rare earth-based intermetallics and in conventional intermetallics are investigated, within the framework of fully anisotropic elasticity supplemented with the atomistic information obtained from the ab initio calculations. Moreover, the evolution and interaction of dislocations in these intermetallics as well as the role of solute segregation are presented by utilizing fully anisotropic 3D dislocation dynamics. The results from this work clearly indicate the role and the importance of …

Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H2 and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. …

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The authors present a measurement of B({pi}{sup 0} {yields} e{sup +}e{sup -}{gamma})/B({pi}{sup 0} {yields} {gamma}{gamma}) using data taken in 1999 by the E832 KTeV experiment at Fermilab. The {pi}{sup 0}s were produced by K{sub L} decays in flight that are fully reconstructed. They find 63,693 K{sub L} {yields} 3{pi}{sup 0} {yields} {gamma}{gamma} {gamma}{gamma} e{sup +}e{sup -}{gamma} decays in KTeV data (an increase of a factor of {approx} 20 in event statistics over previous experiments), and normalize to K{sub L} {yields} 3{pi}{sup 0} {yields} 6{gamma}, to extract B({pi}{sup 0} {yields} e{sup +}e{sup -}{gamma}, m{sub e{sup +}e{sup -}} > 15 MeV/c{sup 2})/B({pi}{sup 0} {yields} {gamma}{gamma}) = (3.920 {+-} 0.016 {+-} 0.036) x 10{sup -3}, where the first error is statistical and the second is systematic. Using the Mikaelian and Smith prediction for the e{sup +}e{sup -} mass spectrum as implemented in the KTeV Monte Carlo to correct to the full e{sup +}e{sup -} mass range yields B({pi}{sup 0} {yields} e{sup +}e{sup -}{gamma})/B({pi}{sup 0} {yields} {gamma}{gamma}) = (1.1559 {+-} 0.0046 {+-} 0.0107)%. This result is consistent with previous measurements and with theoretical predictions, and the uncertainty is a factor of three smaller than any previous measurement.

We studied several {Xi}{sub c}{sup +} decay modes, most of them with a hyperon in the final state, and determined their branching ratios. The data used in this analysis come from the fixed target experiment SELEX, a multi-stage spectrometer with high acceptance for forward interactions, that took data during 1996 and 1997 at Fermilab with 600 GeV=c (mainly {Sigma}{sup -}, {pi}{sup -}) and 540 GeV/c (mainly p) beams incident on copper and carbon targets. The thesis mainly details the first observation of two Cabibbo-suppressed decay modes, {Xi}{sub c}{sup +} {yields} {Sigma}{sup +}{pi}{sup -}{pi}{sup +} and {Xi}{sub c}{sup +} {yields} {Sigma}{sup -}{pi}{sup +}{pi}{sup +}. The branching ratios of the decays relative to the Cabibbo-favored {Xi}{sub c}{sup +} {yields} {Xi}{sup -}{pi}{sup +}{pi}{sup +} are measured to be: {Lambda}({Xi}{sub c}{sup +} {yields} {Sigma}{sup -}{pi}{sup +}{pi}{sup +})/{Lambda}({Xi}{sub c}{sup +} {yields} {Xi}{sup -}{pi}{sup +}{pi}{sup +}) = 0.184 {+-} 0.086. Systematic studies have been performed in order to check the stability of the measurements varying all cuts used in the selection of events over a wide interval and we do not observe evidence of any trend, so the systematic error is negligible in the final results because the quadrature sum of the total error is not …

One of the major highlights of the technology development for the National Ignition Facility (NIF) is the optics. NIF will be the largest laser ever built, requiring 7500 large optics (over one foot across) and more than 30,000 small optics. The design, manufacture, and assembly of these important pieces have called for innovative ways to make optics of higher quality than ever before, and to do so at unprecedented speeds. The most obvious role of NIF optics is to steer the 192 laser beams through the 700-foot-long building onto a dime-size laser-fusion target. The less obvious optic roles are using NIF laser glass to create laser light out of normal light, and using KDP crystals to convert that laser light to the correct frequency; both of which are technically challenging requirements. The Optics Processing Laboratory and Optics Assembly Building enable the final preparation and mounting of these amazing optics for their use in NIF.